1. Field of the Invention
The present invention relates to a flat bed knitting machine of the type having, in needle slots in needle beds, knitting needles jacks for controlling the movement of the needles, and selector jacks for actuating the needle-actuating jacks, there being selectors electrically operable or controllable for selecting selector jacks, so that a combination of knitting, tucking, and non-knitting can be performed in one course.
2. Prior Art
Knitting machines are well known in which electrically operated or controlled selectors push and tilt selected selector jacks for retracting their butts out of the camming action. With such type of knitting machine, however, only a combination of two out of knitting, tucking and non-knitting is possible to be effected in one course. Several flat bed knitting machines are known in which a combination of knitting, tucking and non-knitting can be performed in one course.
One of such knitting machines is a Jacquard flat knitting machine disclosed in U.S. Pat. No. 3,304,748. With this knitting machine, however, needle selection is carried out mechanically, but not electrically, as is well known.
Another such knitting machine is disclosed in U.S. Pat. No. 3,955,381. The disclosed flat bed knitting machine has in each needle slot in a needle bed a knitting needle, a jack for controlling movement of the knitting needle, a selector jack for operating a needle-actuating jack, and a selector movable in accordance with a pattern, the selector jack being available in a variety of shapes with convexities or projections located in varying positons on stems. By engaging the selector with the convexity and pushing the same, the selector jack is caused to flex in the needle slot, enabling the butt thereon to be positioned out of camming action. With such an arrangement, while several kinds of selector jacks are selectively positionable in accordance with a pattern, those selector jacks having convexities located in the same position are only allowed at all times to locate the needles associated therewith in either knitting, tucking or non-knitting position. In other words, such needles are not positionally selectable between two or more different positions. Accordingly, the selector jack must be changed in position each time a different pattern is to be used. Another problem is that the selector jack is subject to repeated flexing through a number of needle selections and hence tends to be broken soon. One solution would be to use a long jack which is free of early breakage; however, it would result in an enlarged needle bed.
Still another type of flat bed knitting machine shown in U.S. Pat. No. 3,693,377 has selectors that are electrically operable or controllable in accordance with a pattern.
With such knitting machine, selector jacks are advanced on the cam formed on a selector, and the selector for advancing the selector jacks must be held in engagement with the convexity on a stem of the selector jack at least during the advancing movement. As the carriage travels faster, therefore, the selector tends to engage the convexity of a next selector jack before the selector is returned completely. For enabling the selector to engage the convexity of a desired selector jack only in order to select needles correctly, it is necessary to move the carriage at a lower speed, or to have a longer distance between adjacent convexities positioned in the same location. A variety of kinds of selector jacks having differently positioned convexities, and a multiplicity of selectors and a selector actuator would be required for that purpose, resulting in a complicated knitting machine. Furthermore, the jacks are bent so as to allow the butt to be retracted out of the camming action, so that the jacks are also liable to be broken with this type of flat bed knitting machine.